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Synergistic Effects of Multiple Metal Contaminants on Electrokinetic Remediation of Soils
Author(s) -
Reddy Krishna R.,
Chinthamreddy Supraja,
AlHamdan Ashraf
Publication year - 2001
Publication title -
remediation journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.762
H-Index - 27
eISSN - 1520-6831
pISSN - 1051-5658
DOI - 10.1002/rem.1006
Subject(s) - electrokinetic remediation , environmental chemistry , soil water , environmental remediation , electrokinetic phenomena , adsorption , desorption , chemistry , contamination , precipitation , soil contamination , dissolution , environmental science , soil science , organic chemistry , biology , meteorology , ecology , physics
This article presents a bench‐scale study performed to investigate the removal of heavy metals whenthey exist individually and in combination in soils. Electrokinetic experiments were conducted using two typesof clayey soils, kaolin and glacial till. These soils were contaminated with Cr(VI) only, withNi(II) only, and with Cr(VI), Ni(II), and Cd(II) combined. It was foundthat in kaolin, a significant pH variation occurred due to electric potential application, affecting theadsorption‐desorption and dissolution‐precipitation, as well as the extent of migration of thecontaminants. In glacial till, however, pH changes were not affected significantly. In both kaolin and glacialtill, the migration of Cr(VI) and Ni(II) was higher when they were present individuallycompared to when they existed together with Cd(II). Cr(VI) migration as single or combinedcontaminant was lower in kaolin as compared to that in glacial till. This result was due to the low pHconditions created near the anode region in kaolin that led to high Cr(VI) adsorption to the claysurfaces. In glacial till, however, nickel precipitated with or without the presence of co‐contaminantsdue to high pH conditions in the soil. Overall, this study demonstrates that adsorption, precipitation, andreduction are the significant hindering mechanisms for the removal of heavy metals using electrokineticremediation. The direction of the contaminant migration and overall removal efficiency depend on the polarity ofthe contaminant, the presence of co‐contaminants, and the type of soil. © 2001 John Wiley &Sons.